Delta-sigma modulator having sensor front-end

• US 9,407,283 B2
• Filed: 10/17/2013
• Issued: 08/02/2016
• Est. Priority Date: 10/17/2013
• Status: Active Grant

• Current Assignee: Analog Devices International Unlimited Company (Analog Devices, Inc.)
• Original Assignee: Analog Devices Global Unlimited Company (Analog Devices, Inc.)
• Inventors: Caldwell, Trevor Clifford, Schreier, Richard E.
• Primary Examiner(s): LAUTURE, JOSEPH J
• Application Number:
  US14/055,980
• Publication Number:
  US 20150109157A1
• Time in Patent Office: 1,020 Days
• Field of Search: 341/143, 341/155, 341/156, 341/136, 341/120
• US Class Current: 1/1
• CPC Class Codes: G01R 19/25 using digital measurement techniques
• CPC Class Codes: H03M 1/00 Analogue/digital conversion; Digital/analogue conversion conversion of analogue values to or from differential modulation H03M3/00
• CPC Class Codes: H03M 1/12 Analogue/digital converters H03M1/001 – H03M1/10 take precedence
• CPC Class Codes: H03M 3/30 Delta-sigma modulation
• CPC Class Codes: H03M 3/458 Analogue/digital converters using delta-sigma modulation as an intermediate step

Abstract

A delta-sigma modulator is configured to sense and convert an electromagnetic field into a digital signal. An exemplary delta-sigma modulator includes a sensor component, such as an LC resonator, that is configured to sense the electromagnetic field and generate an input analog signal, where the delta-sigma modulator is configured to convert the input analog signal to the digital signal. Delta-sigma modulator can include an analog-to-digital converter coupled to the sensor component that receives and converts the input analog signal to the digital signal. Delta-sigma modulator can further include a digital-to-analog converter (DAC) coupled to the resonator and the ADC, the DAC configured to receive the digital signal from the ADC and generate a feedback analog signal.

Claims

1. A circuit comprising:

a delta-sigma modulator that is configured to sense and convert an electromagnetic field into a digital signal, wherein the delta-sigma modulator includes an LC resonator configured to sense the electromagnetic field and generate an analog signal, the delta-sigma modulator configured to convert the analog signal to the digital signal.

2. The circuit of claim 1, wherein an inductor of the LC resonator is configured to sense a magnetic field, such that a current induced by the sensed magnetic field provides the analog signal.

3. The circuit of claim 1, wherein a capacitor of the LC resonator is configured to sense an electric field, such that a voltage induced by the sensed electric field provides the analog signal.

4. The circuit of claim 1, wherein the delta-sigma modulator further includes an analog-to-digital converter coupled to the LC resonator, the analog-to-digital converter configured to convert the analog signal to the digital signal.

5. The circuit of claim 4, wherein the delta-sigma modulator further includes a digital-to-analog converter coupled to the LC resonator and the analog-to-digital converter, such that the digital-to-analog converter is configured to receive the digital signal from the analog-to-digital converter and generate a feedback analog signal, wherein the LC resonator is configured to receive the feedback analog signal.

6. The circuit of claim 1, wherein the delta-sigma modulator directly converts the electromagnetic field into the digital signal.

7. The circuit of claim 1, wherein the LC resonator is a first stage resonator of a plurality of resonators of the delta-sigma modulator.

8. The circuit of claim 1, wherein the delta-sigma modulator is a band-pass delta-sigma modulator.

9. The circuit of claim 1 further comprising a digital filter/decimator component coupled to the delta-sigma modulator, wherein the delta-sigma modulator and the digital filter/decimator component form a delta-sigma analog-to-digital converter.

10. The circuit of claim 9 further comprising a digital signal processor coupled to the delta-sigma analog-to-digital converter.

11. A delta-sigma modulator configured to generate an output signal that is a digital representation of an input signal, the delta-sigma modulator comprising:

a resonator configured to sense an electromagnetic field and generate the input signal for the delta-sigma modulator;

an analog-to-digital converter (ADC) coupled to the resonator, the ADC configured to receive the input signal and generate the output signal; and

a digital-to-analog converter (DAC) coupled to the resonator and the ADC, the DAC configured to receive the output signal from the ADC and generate a feedback input signal.

12. The delta-sigma modulator of claim 11, wherein the resonator is an LC resonator.

13. The delta-sigma modulator of claim 12, wherein the LC resonator includes an inductor and a capacitor connected in parallel.

14. The delta-sigma modulator of claim 12, wherein the LC resonator is configured as an inductive sensor, such that an inductor of the LC resonator senses a magnetic field and a current induced by the sensed magnetic field provides the input signal.

15. The delta-sigma modulator of claim 12, wherein the LC resonator is configured as a capacitive sensor, such that a capacitor of the LC resonator senses an electric field and a voltage induced by the sensed electric field provides the input signal.

16. The delta-sigma modulator of claim 11 further comprising a buffer coupled with the resonator and the ADC.

17. The delta-sigma modulator of claim 11, wherein the resonator is a first stage resonator of a plurality of resonators of the delta-sigma modulator.

18. The delta-sigma modulator of claim 11, wherein the input signal is an analog signal and the output signal is a digital signal.

19. A method comprising:

sensing, by a resonator of a delta-sigma modulator, an electromagnetic field;

generating, by the delta-sigma modulator, an analog signal representing the electromagnetic field; and

converting, by the delta-sigma modulator, the analog signal to a digital signal.

20. The method of claim 19, wherein:

the delta-sigma modulator includes a resonator for sensing the electromagnetic field and generating the analog signal, wherein the generating the analog signal includes inducing a current or a voltage in the resonator upon the resonator sensing the electromagnetic field.